Torsion shaft



Dec. 28 1926.

C. R. SODERBERG TORS ION SHAFT Filed June 26. 1923' Patented Dec. 28, 1926.

UNITED STATES PATENT OFFICE.

CARL RICHARD SODEBBIER'r7 OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC 8c MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

TORSION SHAFT.

VApplication lcd .Tune 26,

My invention relates to flexible drive elements and more especially to flexible shafts such as are employed in connection with rotors of dynamo-electric machines and the like.

vlt is among the objects of my invention to proviil?l a liexiblo shaft which is of simple, durable. mechanical construction, which is :nlapted generally as a torsional drive shaft where it is desired to obtain a limited degree of flexibility and which is adapted to previde a relatively large amount of flexure for the size or cross-section of shaft employed.

The object of flexible drive elements is to provide a yielding nredinni betr-cen the drivn ing and the driven members to avoid excessive stresses resulting from impact and shock which are detrimental to the more sensitive parts of the device utilized. To this end.y various schemes have been developed of which the most common form is the flexible gear which more readily adapt-s itself to the design of a definite degree of flexure that is deemed essential for specific applications. The gear structure, however, has certain inherent difficulties such as the performance of the spring members which may be of the leaf or coil type both of which are dependent upon the uniformity in quality and mannfacture.

Another' development has been the flexible sha ft vihieh. in its common acceptation, comprises ay hollow shaft pressed into the rotor or an armature having a flexible shaft of a reduced or restricted working body portion disposed therein and secured to one end or to the center' thereof. The fit between the remaining cooperating portions of the rigid and the flexible member is relatively loose to constitute what is known as a shivering fit. This bearing must be lubricated and this condition offers fundamental difficulties due principally to the eccentricity of the rotor.

My present invention is directed to a .fiexible drive shaft which obviates the above enmnerated difficulties in that it provides a high degree of torsional flexibility without reducing the body portion of the shaft member. Such a shaft is rigid and adequately withstands the lateral and bending stresses and yet provides a sufficient degree of torsional fiexure requisite for certain applications.

1923. Serial No. 647.773.

ln the acconilpanying drawing constituti ng a part hereof and in which like reference characters designate like parts,

Fig. l is a view. partially in longitudinal section and partially in elevation of a flexible d rive element embodyin 'gr the principle of my invention, constituted in a rotor such as an armature of a dynanio-electric machine,

Fig'. 2 is a view, partiall'x.r in longitudinal section and partially in elevation, of a flexible shaft such as is utilized in the rotor Fig'. 1,

Fig. 3 is a cross-sectumal view taken along the line 3--3 of Fig. 2,

Fig'. i is a modification of the shaft shown in Fig. 2 and Fig. is a cross-sectional view thereof taken along the line 5--5 of Fig., et.

Referring to Figs. l, 2 and 3, an armature shaft l is pressed into the rotor 2 in the usual manner, the rotor constituting the arl'natnre of a dynamo-electric machine. The shaft l is provided with a reduced body portion 3, and enlarged bearing portion 4 and tapered end portion 5 adapted to ref ceive a gear wheel that is secured thereon by a nut threaded on the screw thread 6.

rA sleeve 7 extending from the shoulder of the large portion 4. to the edge of the tapered seating portion 5 is mounted on the shaft l by securing it with a pressed fit on the diameters 8 and 9.

The sleeve 7 is provided with a plurality of symmetrically disposed radially extending slots l() extending axially along a restricted longitudinal portion in alignment with the reduced body portion 3 of the shaft l. The object of thus relieving the sleeve member is to provide a relatively stiff section through the slotted portion to effectively restrict lateral and bending stresses and yet permit adeipiate torsional flexibility which is provided by the reduced portion 3 of the shaft l.

In Figs. 2 and 3 the shaft portion i, is an integral extension of the shaft 9 and the sleeve 7 is an integral part of the shaft portion 8. The sleeve '7 is assembled on the shaft portion 3 by a press or shrink fit at the shoulders 17 thereof.

Referring to Figs. 4 and 5, the modification shown therein consists of a shaft 11 of uniform crosssection throughout and having a restricted body portion relieved by a plurality of radial slots l5 to provide a small section 16 of relatively small proportion as compared with the entire section of the shaft. This design permits of torsional flexibility coupled with the strength and rigidity of a much larger section. I`l1e function of this modified form is similar to that embodying` the reduced section and supporting sleeve member Figs. l and 2.

The dimensions of the slots or recesses l5 vary with the requirements for flexibility strength, ets., but the Width of the slots should be maintained at a minimum in so far as is consistent With practical manufacturing' operations. Y

It is evident from the above description of my invention that flexible shafts embodied in drive mechanisms made in accordance therewith provide a high degree of t-orsional flexibility coupled with durability, rigidity and relatively great mechanical strength and that such a shaft is particularly adapted to resist lateral and bending stresses resulting from the severity of the service and the torque transmitted.

Although I have described a specific em bodiment of my invention, it vvill be obvious to those slgilled in the art that various modifications may be made in the details of construction Without departing from the prinoiples herein set forth. For instance: The

number and location of the'slots or recesses in the shafts may be varied in accordance with the specific requirements of the particular service application and the diameters of the shaft and sleeve members may vary from those illustrated in the drawing, also such shafts need not be utilized in rotors such as I have illustrated but may be journaled in the ordinary manner on pillar block bearings or in axle housings of vehicles or the like.

I claim as my invention:

l. A solid flexible shaft of substantially uniform diameter having a solid `center and axial slots radiating therefrom.

2. A solid flexible shaft of substantially uniform Vdiameter having a solid Acenter and axial slots provided in a portion thereof.

S. A solid fieXible shaft of substantially uniform diameter having a plurality of nonintersecting symmetrically disposed slots of a predetermined depth provided therein.

Il. A solid flexible shaft of substantially uniform diameter having` a plurality of nonintersecting` radial slots symmetrically disposed and of a predetermined depth provided therein.

In testimony whereof, I have hereunto subscribed my name this 12th day of June, 1923.

CARL RICHARD SODERBERG. 

